The present disclosure relates to a light detecting chip. More particularly, the present disclosure relates to a light detecting chip and a light detecting device provided with the light detecting chip, which are used for analysis of gene expression, examination of infectious disease, gene analysis (such as SNP analysis), protein analysis, and cell analysis.
Comprehensive research and development on gene analysis, protein analysis, and cell analysis are going on in various fields including medical service, innovative drug development, clinical laboratory test, food industry, agriculture, engineering, legal medicine, and criminal identification. Conspicuous among them is a new technology of “lab-on-chip” which permits various reactions (for detection and analysis of nucleic acids, proteins, and cells) to take place in a channel or well of micro scale formed in a chip. It is now attracting attention because of its potential capacity for measuring biomolecules in a simple way.
The problem with the lab-on-chip technology is that mixing, reaction, separation, purification, and detection have to be carried out with an extremely small amount of sample in the channel or well of micro scale formed in a chip. For efficient detection and analysis, it is necessary to contrive good ways and means for chip design and their implementation.
For example, there is proposed in Japanese Patent Laid-open No. 2008-015770 (Patent Document 1) a chip with a micro channel formed therein. This chip is designed such that a reagent mixed with a thermally fusible binder is supported at a prescribed position in the micro channel. After introduction of a sample solution, the chip is heated so that the thermally fusible binder begins to melt at the position where it is supported. This leads to efficient dissolution and mixing and permits the subsequent reaction and analysis to take place at the same position. The result is that it is possible to reduce the number of spots for reaction in the micro channel, which leads to size reduction and cost reduction.
There is proposed in Japanese Patent Laid-open No. 2007-139744 (Patent Document 2) a fluorescence polarization assay which is capable of analysis with a very small amount of sample (about one-hundredth the amount used in the assay in the related art). The assay includes (1) a step of preparing fluorescent probe molecules and biomolecules, (2) a step of injecting them into the micro channel of a Lab-on-a-chip, thereby forming their complex, (3) a step of directing a beam of polarized light to the complex and measuring fluorescent polarization caused by the complex, and (4) a step of quantifying the fluorescent polarization and determining the degree of fluorescent polarization.
There is proposed in Japanese Patent Laid-open No. 2008-17779 (Patent Document 3) a Lab-on-chip which is composed of the following units arranged on a single substrate. A unit for preparation of nucleic acid, which is provided with a first electrode; a unit for introduction of a sample fluid into the nucleic acid preparing unit; a reaction unit communicating with the nucleic acid preparing unit through a channel, the reaction unit being provided with a second electrode; a unit for introduction of drug solution into the reaction unit; a unit for discharge of fluid from the reaction unit; a control circuit connected to the first and second electrodes; and a detecting circuit connected to the second electrode. This Lab-on-chip is capable of replication, synthesis, reaction, and detection of nucleic acids on a single substrate.
There is proposed in Japanese Patent Laid-open No. 2007-187582 (Patent Document 4) a biochip which is provided with detectors (such as working electrode, reference electrode, and counter electrode) and thin-film transistors. This biochip will find use as a biosensing device which is light, thin, short, small, and cheap and yet capable of high performance. It can also be detachably mounted on a biosensor provided with an ink jet head.